hg: panama/dev: 8238466: add jtreg test driver for jextract tool

[sundararajan.athijegannathan at oracle.com]

Changeset: a58f76f7ddc8
Author:    sundar
Date:      2020-02-04 17:49 +0530
URL:       https://hg.openjdk.java.net/panama/dev/rev/a58f76f7ddc8

8238466: add jtreg test driver for jextract tool
Reviewed-by: mcimadamore

! src/jdk.incubator.jextract/share/classes/jdk/incubator/jextract/tool/JavaSourceBuilder.java
! test/jdk/TEST.groups
+ test/jdk/tools/jextract/JtregJextract.java
! test/jdk/tools/jextract/hello.h
+ test/jdk/tools/jextract/testStruct/LibStructTest.java
+ test/jdk/tools/jextract/testStruct/libStruct.c
+ test/jdk/tools/jextract/testStruct/struct.h